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Wooden Lead Screws 


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Wooden Lead Screws 

Written By: Alan Federman 


By using a router and a countersink bit, you can make wooden screws of different 
diameters. The results are pretty good. 

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Wooden Lead Screws 

Step 1 — Wooden Lead Screws 

• Wooden Screws Part II: As part of 
my continued exploration of 
Leonardo Da Vinci mechanisms, I 
needed to produce several different 
kinds of lead screws and nuts for 
my projects. While commercial 
wood taps and dies are relatively 
inexpensive, I wanted to make my 
own, so I could get the right 
diameter and pitch. During my 
efforts I tread making several 
different kinds of taps, but wasn't 
too successful making the old- 
fashioned screw boxes. Information 
on doing this can be found in Roy 
Underbill's books on woodworking. 

• There is another technique for 
making wooden screws on a wood 
lathe called "chasing threads" but 
this takes special equipment and 
years of experience. Eventually, I 
built a couple of "screw 
duplicators" using a table-mounted 
router and salvaged lead screws, 
and these worked very well. 

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Wooden Lead Screws 

Step 2 

• I used the lead screw borrowed 
from my bench vise, which had 
about 4.5 threads per inch, for 
screws made out of 1 " poplar 
dowel. I used scraps of oak, 
mahogany, and some plywood to 
build a mechanism that can both 
feed and rotate the blank through 
the cutter. A drill press helps make 
sure the holes drilled are at right 
angles to the bearing blocks. A 
small 1/16" hole drilled through the 
end block and a short length of 
brass wire are used to pin the end 
block to the lead screw. 

• The whole jig was screwed onto the 
router table and the height of the 
router was adjusted for the proper 
depth of cut. 

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Wooden Lead Screws 

Step 3 

• I used an inexpensive countersink 
bit in my router and this seemed to 
give good results. I am sure a 
carbide "V" cutter would work as 
well or better. This rig works 
remarkably well. I've built a second 
similar rig for producing 0.5 inch 
screws up to 1 foot in length. 

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Wooden Lead Screws 

Step 4 

• The method for making taps is 
explained in detail in this 
reference^ ). An approximate rule 
of thumb is that you need a piece 
of square stock 75% of the 
diameter of the screw you're 
cutting the nut for. So for a 1" 
screw, you need a W square steel 
rod. These taps work well up to a 
1" diameter. 

• Briefly, a triangular strip of paper is 
used to transfer the thread to the 
stock. This is glued on to the 
square rod, and then a triangular 
file is used to notch the work piece. 
Then file away. It takes about two 
hours of filing to make a tap. 

• For nuts over 1" a tap box is 
needed. A tap box uses an interna 

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Wooden Lead Screws 

Step 5 

• Though I had some success 
making V2" nuts via my tap, I found 
for my project that a piece of 12- 
gauge copper wire used as a lead- 
screw follower worked better. 

• I needed the lead screws for the Da 
Vinci File Cutter. In this device, a 
trip hammer repeatedly impacts an 
iron blank as the work is advanced 
by the lead screw. 

• Here is a YouTube Link. 

This document was last generated on 2012-11-03 01 :28:40 AM. 

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